Does a SIM card consist of only Flash memory or is there a microprocessor inside as well?

  • My answer was incorrect. It has been updated.
    – julian
    Commented Mar 22, 2017 at 13:50
  • How does this related to reverse engineering?
    – phuclv
    Commented Mar 24, 2017 at 9:19
  • @SDsolar first post or not isn't an explanantion for it on this site. It's off topic and this should be on electronics.stackexchange.com
    – phuclv
    Commented Mar 25, 2017 at 3:58
  • 2
    I'm voting to close this question as off-topic because it is about regular hardware usage.
    – perror
    Commented Mar 25, 2017 at 8:34
  • This question can be closed if that's the wish of the majority. I don't have any problem because I've already asked the question at the right forum (as was suggested). Commented Mar 25, 2017 at 10:05

1 Answer 1



in fact many SIMs do contain a microprocessor for extra functionality (see SIM Application Toolkit).

Thank you Igor Skochinsky for the correction.

According to Karsten Nohl's presentation "Mobile Network Attack Evolution", SIM cards contain an embedded real-time operating system, a filesystem and a Java VM :

Presentation slide 1

Slide 2

Here is a direct link to the presentation: https://www.slideshare.net/phdays/140521karsten-nohl-phdmobileattackevolution-35161629

See also: 4G Security: Hacking USB Modem and SIM Card via SMS

  • Excellent information. I recently bought a $10 gadget called a "SIM card reader" but it shows nothing when I plug it into the USB port. I suppose it must require some fancy software to make all this work, eh?
    – SDsolar
    Commented Mar 24, 2017 at 8:10
  • I don't know but I'm sure that someone else here will. Maybe post a question about it?
    – julian
    Commented Mar 24, 2017 at 14:20
  • Thanks for the info. However I'd like to know a few more things: 1. Since which generation did the SIM cards start to have a microprocessor? I mean, was it after 2G, 3G or 4G? 2. Mainly which microprocessor is used in the SIMs? Commented Mar 25, 2017 at 3:18
  • http://simhacks.github.io/sim-cards/
    – julian
    Commented Mar 25, 2017 at 3:34
  • I couldn't find anywhere explicitly written that SIM cards contain microprocessor. Why do you think we don't have info about the microprocessors being used in our modern SIM cards like we have in the case of smartphones? Commented Mar 25, 2017 at 3:39

Not the answer you're looking for? Browse other questions tagged or ask your own question.